Answer: cos(theta) = 2/3.
- A cos(theta) = 2/3
- B cos(theta) = 1
- C cos(theta) = 2
- D cos(theta) = 4/3
Correct answer: A. cos(theta) = 2/3
Explanation: cos(theta) = a.b / (|a||b|) = 4/(3 x 2) = 4/6 = 2/3. theta = cos<sup>-1</sup>(2/3).
Triangle law of vector addition: placing vector b at the head of vector a, the diagonal from the start to the final head gives the resultant a + b.
Concept context
Vectors, dot product, cross product, and geometric applications